Abundo R., Canonica M., Corrente G.

Decision criteria in choosing between Endodontic retreatment and implants

Endodontic retreatment in modern dentistry
All teeth can be treated with endodontic means, if you can assure adequate cleaning, shaping and filling of the root system (1) (fig.1).

Fig. 1

A prominent innovation in endodontics has been the introduction of nickel-titanium instruments.

Thanks to the properties of this alloy, these instruments provide a good cleaning and shaping in an easy and relatively rapid way, enlarging the curved canals and preserving the original anatomy, thanks to a circumferential reaming along its axis (fig.2).

Fig. 2

Similarly, the operative microscope, just recently introduced in the field, has shown great potential.

It has completely changed the operative methods in endodontics, so that a great number of orthograde and surgical operations, otherwise complex, have become highly predictable and simple to perform.

For non surgical procedures, the microscope can be used in the different phases of endodontic therapy: operations like negotiating a ledge, removing a broken instrument or repairing a perforation have become much safer.

Likewise, the possibilities and precision of endodontic surgery have significantly improved in the last few years.

The microscope, together with the micro-surgical approach, with the miniaturized instruments, adequate aspiration and perfect hemostasis, allow for the non-traumatic treatment of the soft tissues, the complete visualization of the root apex, the preparation of the retrograde cavity and the position of the filling material in a completely dry field (fig. 3). The introduction of the ultrasonic points for preparation of the retrograde cavity has produced great operative and clinical advantages.

Fig. 3

The introduction of these inserts has allowed the execution of ideal retrograde cavities, in axis with the root canal and adequately cleaned, that would have been impossible to achieve with the handpiece bur.

A recent longitudinal study by Rubinstein and Kim (2) showed the high rate of success of surgical endodontics, by means of the instruments and techniques here described. The success rate is 96.8 %, with a mean recovery time of 7.2 months.

We can therefore sustain that the progress of instruments and techniques allows for good results even in endodontic retreatments.

Prognosis of endodontic retreatment
The long-term outcome of endodontic treatment is difficult to evaluate.

Only a statistical study, including all possible measures of success and failure, could reach unequivocal conclusions (3).

Nevertheless, thanks to the current operative tools, we can affirm that endodontic retreatment presents a reasonably good prognosis (4) (fig. 4-5).

Fig. 4

Fig. 5

Endodontic indications for implantology
The degree of complexity of endodontic retreatment is not a sound reason to decide whether a tooth should be saved or extracted (5).

Rather, we should analyze other non-endodontic factors, whose consideration should guide our operative decisions (6) (fig. 6).

Fig. 6

Prior to the endodontic treatment, we must consider the pre-operative condition of the tooth and perform an anatomo-morphological analysis of the root and crown (fig. 7-8).

Fig. 7

Fig. 8

Among possible contraindications of endodontic retreatment are the following (7, 8):

• unfavorable root anatomy (shape, taper, residual dentine thickness, brittleness)
• insufficient crown/root ratio
• shedding (root resorption) and perforations
• root or bifurcation caries

We must consider the pre-existing re-constructive factor and eventually the one subsequent to our retreatment.

Pre-existing restorations with excessive B/L (bucco-lingual) extension may have led to cracks and fractures that, if undetected, are responsible for frustrating failures (fig. 9).

Fig. 9

The tooth could not allow for a reliable post-endodontical prosthetic restoration.

The patient could not understand the need for an immediate restorative therapy, thus becoming responsible for the failure of a delayed treatment.

We must restoratively consider the root retentions.

Pre-existing endo-canal retentions may cause significant tensions in the dentine, particularly in the pre-molar/molar region (fig. 10).

Fig. 10

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